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std/async/pool_test.ts

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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.import { delay } from "./delay.ts";import { ERROR_WHILE_MAPPING_MESSAGE, pooledMap } from "./pool.ts";import { assert, assertEquals, assertRejects, assertStringIncludes,} from "../testing/asserts.ts";
Deno.test("[async] pooledMap", async function () { const start = new Date(); const results = pooledMap( 2, [1, 2, 3], (i) => new Promise((r) => setTimeout(() => r(i), 1000)), ); const array = []; for await (const value of results) { array.push(value); } assertEquals(array, [1, 2, 3]); const diff = new Date().getTime() - start.getTime(); assert(diff >= 2000); assert(diff < 3000);});
Deno.test("[async] pooledMap errors", async () => { async function mapNumber(n: number): Promise<number> { if (n <= 2) { throw new Error(`Bad number: ${n}`); } await delay(100); return n; } const mappedNumbers: number[] = []; const error = await assertRejects(async () => { for await (const m of pooledMap(3, [1, 2, 3, 4], mapNumber)) { mappedNumbers.push(m); } }, AggregateError); assert(error instanceof AggregateError); assert(error.message === ERROR_WHILE_MAPPING_MESSAGE); assertEquals(error.errors.length, 2); assertStringIncludes(error.errors[0].stack, "Error: Bad number: 1"); assertStringIncludes(error.errors[1].stack, "Error: Bad number: 2"); assertEquals(mappedNumbers, [3]);});
Deno.test("pooledMap returns ordered items", async () => { function getRandomInt(min: number, max: number): number { min = Math.ceil(min); max = Math.floor(max); return Math.floor(Math.random() * (max - min) + min); //The maximum is exclusive and the minimum is inclusive }
const results = pooledMap( 2, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], (i) => new Promise((r) => setTimeout(() => r(i), getRandomInt(5, 20) * 100)), );
const returned = []; for await (const value of results) { returned.push(value); } assertEquals(returned, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);});